A Pyridinium Ylide-Alkylation\nStrategy for the Structural\nDiversification of <i>N</i>‑Carbamoylpyridinium Salts

A pyridinium ylide-alkylation strategy\nhas been developed\nfor selectively\naccessing <i>N</i>,<i>N</i>-disubstituted pyridinium\nsalts from monosubstituted pyridinium salts possessing ambident nucleophiles.\nThe method was shown to be tolerant toward an array of different pyridinium\nscaffolds and common electrophiles, enabling access to structurally\ndiverse pyridinium salts. The potential versatility of the approach\nwas demonstrated through the synthesis of chemically complex, heterotrifunctional\npyridinium salts containing a pyridinium warhead, a click chemistry\nhandle, and a third, high-value, payload.